PLATE XXXVlll. 



Fig. I. Venus halidona Dall. right valve, enlarged to bring out sculpture; Ballast 

 Point, Tampa Bay, Florida, silex beds ; Ion. 37 mm. 



Fig. la. The same, umbonal view. 



Fig. 2. Venus tarquinia Dall, = /". magnified Heilprin non Sowerby, left valve, en- 

 larged slightly; Ion. 49 mm.; Ballast Point silex beds. 



Fig. 2a. The same, umbonal view. 



Fig. 3. Tcllina (Mcrisca) halidona Dall; Ballast Point silex beds; Ion. 14.5 mm.; 

 p. 1021. 



Fig. 33. The same, inside view; p. 1021. 



Fig. 4. Area umbonata Lamarck; from above; Ballast Point silex beds; Ion. 36.0 

 mm. ; p. 620. 



Fig. 43. The same, inside view of left valve ; p. 620. 



Fig. 5. Lcda flcxuosa Heilprin, type specimen ; Ion. 14.25 mm. ; p. 589. 



Fig. sa. The same, dorsal view. 



Fig. 6. Scincle silicata Dall ; Ballast Point silex beds ; Ion. 23.0 mm. ; p. 987. 



Fig. 7. Cyrcna t>omt>liolyx Dall, interior view of right valve ; from the Ballast Point 

 silex beds ; Ion. 43 mm. 



Fig. 8. The same, external view. 



Fig. 9. Cardita scrricosta Heilprin, interior view of a silicious psetidoniorph. natural 

 size; Ballast Point silex beds. 



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